About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Ultrafine-Grained and Heterostructured Materials (UFGH) XIV
|
| Presentation Title |
Dislocation-Phonon Interactions in Ultrafine-Grained and Nanocrystalline Metals at Ultra-High Strain Rates |
| Author(s) |
Mostafa Hassani, Laura Wu, Luyan Li |
| On-Site Speaker (Planned) |
Mostafa Hassani |
| Abstract Scope |
At extreme deformation rates, dislocation motion transitions from thermally activated glide to ballistic transport. This shift leads to intensified interactions between dislocations and phonons, which can cause embrittlement and ultimately catastrophic failure. In this talk, we demonstrate that confining dislocation motion through microstructural refinement—specifically in ultrafine-grained and nanocrystalline metals—enables distinct mechanical behavior under ultra-high strain-rate deformation, markedly different from that of coarse-grained counterparts. We begin by presenting an integrated experimental and theoretical framework to study dislocation-phonon interactions at strain rates approaching 10⁹ s⁻¹, using in-situ microprojectile impact testing. Our findings show that grain size plays a key role in modulating dislocation-phonon interactions. In particular, we present evidence that the phonon drag regime can be suppressed by decreasing grain size and can be nearly eliminated in nanocrystalline metals. We conclude by discussing the underlying mechanisms and outlining design guidelines for metals and alloys operating under extreme conditions. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Mechanical Properties, |